Methane Carbon Diox Isotopic Flux Melt Zones

[Global Fossil Fuel Emissions]The massive loss of Arctic floating ice was not forecast, nor is it quantitatively understood. What is clear is that the feedbacks intrinsic to the system will eliminate the second half of the permanent ice more quickly than the first half was lost – which occurred, of course, between 1980 and the present. The loss of permanent floating ice in the Arctic initiates a cascade of coupled feedbacks in other climate sub-systems.

In particular, with the inflow of thermal energy into the Arctic basin following the elimination of permanent ice, a reservoir in northern Alaska and Siberia of 2000 GtC of methane and carbon dioxide in the form of clathrates and permafrost is exposed. If but 0.5% of that reservoir is released each year, it will exceed the entire carbon dioxide forcing of the climate by all fossil fuel combustion annually. No comprehensive observation system exists to quantitatively map the flux of methane and CO2 isotopes from melt zones in the high Arctic. This recasts the rate of climate forcing dramatically as displayed in the adjoining figure.

[Key Feedbacks in the Climate System]